Adafruit-circuitpython-si4713

* Update for removal of `stop` kwarg. ([more info](https://github.com/adafruit/circuitpython/issues/2082))

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

To use in CPython, `pip3 install adafruit-circuitpython-si4713`.

Read the [docs](http://circuitpython.readthedocs.io/projects/si4713/en/latest/) for info on how to use it.

* Some fixes for RDS configuration.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

To use in CPython, `pip3 install adafruit-circuitpython-si4713`.

Read the [docs](http://circuitpython.readthedocs.io/projects/si4713/en/latest/) for info on how to use it.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

To use in CPython, `pip3 install adafruit-circuitpython-si4713`.

Read the [docs](http://circuitpython.readthedocs.io/projects/si4713/en/latest/) for info on how to use it.

And updated example to `si4713_simpletest.py`.

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

To use in CPython, `pip3 install adafruit-circuitpython-si4713`.

Read the [docs](http://circuitpython.readthedocs.io/projects/si4713/en/latest/) for info on how to use it.

- Added `setup.py`
- Added PyPI release info to `.travis.yml`
- Updated `requirements.txt`
- Added a more comprehensive `.gitignore`

To use in CircuitPython, simply install the [Adafruit CircuitPython bundle](https://github.com/adafruit/Adafruit_CircuitPython_Bundle).

To use in CPython, `pip install adafruit-circuitpython-si4713`.

Read the [docs](http://circuitpython.readthedocs.io/projects/si4713/en/latest/) for info on how to use it.

Thanks to tannewt for the doing this!